JP2013211371A - Reactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for improving strength of jointing resin filled in a gap and a core while restraining an eddy current in a reactor having a split core.SOLUTION: A reactor 100 disclosed in this specification comprises a core and a coil 8. The core is split into at least two partial cores 2a, 2b. At least the two partial cores 2a, 2b are opposed to each other across a gap, and end faces of the partial cores 2a, 2b faced to the gap are coated with resin 42. The coil 8 is wound around the core. Plural dot-like bumps, or linear grooves not crossing with the other grooves are formed on the end faces of the partial cores 2a, 2b. By forming the plural bumps or grooves, the resin 42 enters into the bumps or grooves, so as to improve strength of jointing the resin 42 and the end faces of the metallic partial cores 2a, 2b. Even when the bumps or grooves are conducted, a conduction face is limited to a dot-like or linear range, and therefore, an eddy current can be restrained.

Description

  The present invention relates to a reactor. A reactor is a passive element using a coil, and is sometimes called an “inductor”.

  In recent years, electric vehicles have been put into practical use and their spread has been expanding. In order to mount a motor for traveling, an electric vehicle is equipped with a power conversion device for driving the motor. Many power converters (typically voltage converters) include a reactor as a major component. A reactor is an element in which a winding (coil) is wound around a metal core. The electric vehicle includes a hybrid vehicle equipped with an engine and a motor, and a fuel cell vehicle.

  In general, the core of the reactor may be divided. Typically, it is divided into a pair of U-shaped cores, or is divided into a pair of U-shaped cores and an I-shaped core disposed therebetween (Patent Documents 1-3). Several methods are known as a method for fixing the divided cores. Hereinafter, the divided cores are referred to as partial cores. In the technique of Patent Document 1, the end surfaces are bonded with an adhesive via a ceramic plate to fix the partial cores. In the technique of Patent Document 2, the entire partial cores arranged in a predetermined positional relationship are covered with resin, and the gap between the partial cores is filled with resin to fix the partial cores to each other. In the technique of Patent Document 3, a resin sheet is placed on the end faces of the partial cores and thermocompression bonded to fix the partial cores.

  Although not directly related to the reactor, Patent Documents 4 and 5 are cited as techniques related to the technique disclosed in this specification and improving the bonding strength between metal and resin. In the technique of Patent Document 4, a groove crossed on the metal surface is provided to join the metal and the resin. According to the technique, the resin enters the groove and the strength of bonding is improved. In the technique of Patent Document 5, when a metal surface is coated with a resin, the metal surface is roughened into a stripe shape, a dotted line shape, a wavy line shape, a knurled shape, or a satin shape. According to the technique, the resin enters the irregularities formed on the metal surface and the bonding strength is improved.

JP 2008-078219 A JP 2011-086801 A JP 2010-103307 A Japanese Patent No. 4020957 JP 2010-294024 A

  In the technique of Patent Document 1, the partial core is bonded and fixed via a ceramic plate. This technology is costly for equipment such as plates, adhesives, and furnaces for bonding and fixing. From the viewpoint of manufacturing cost, it is better to fix the partial core with resin as in the technique disclosed in Patent Document 2 or 3. This is because if it is a resin, a bobbin in which the partial cores are fixed to each other can be manufactured at low cost by an injection molding method. However, in that case, it is necessary to increase the bonding strength between the metal partial core and the resin.

  As a technique for increasing the bonding strength between a metal and a resin, the technique of Patent Document 4 or 5 is known. In any of the techniques described in these documents, unevenness is provided on the joint surface on the metal side, and resin is inserted into the recess to increase the joint strength.

  By the way, if the core of the reactor is entirely conductive, an eddy current is generated inside, and the eddy current generates a counter electromotive force, thereby reducing the efficiency of the reactor. In order to suppress the generation of eddy currents, the reactor core is made of hardened metal particles (typically sintered) with an insulating coating on the surface. Such a core is made of metal but is non-conductive as a whole. When unevenness is provided on the surface of such a core, the insulating coating is peeled off and adjacent particles are brought into conduction. If the groove | channel which cross | crosses the surface of a core like the technique disclosed by patent document 4 is provided, the conduction surface which has a two-dimensional expansion will be formed in the surface of a core, and an eddy current will generate | occur | produce. The present specification relates to a reactor having a divided core, and provides a technique for increasing the bonding strength between the resin filled in the gap and the core while suppressing the generation of eddy currents.

  One aspect of the technology disclosed in this specification can be embodied in a reactor having the following configuration. The reactor includes a core and a coil. The core is divided into at least two partial cores. The at least two partial cores face each other across the gap, and the end faces of the partial cores facing the gap are covered with resin. The reactor further includes a coil wound around the core. A plurality of point-like depressions or linear grooves that do not intersect with other grooves are formed on the end face of the partial core facing the gap.

  The reactor disclosed in this specification includes a plurality of dot-like depressions or linear grooves that do not intersect with other grooves on the end faces (end faces facing the gap) where the partial cores face each other. Typically, the grooves are such that the grooves are parallel to each other, or grooves extending radially from the center). Resin enters the recess or groove, and the bonding strength between the metal partial core and the resin is improved.

  As described above, the partial core is often formed by solidifying metal particles that have been subjected to insulation treatment. Typically, the metal particles that are the raw material of the partial core are subjected to an insulating coating and then sintered. If the partial core is conductive as a whole, an eddy current is generated inside the partial core due to the magnetic flux generated in the coil. Eddy currents are undesirable because they generate counter electromotive force and reduce reactor efficiency. Therefore, as described above, when the metal particles as the raw material of the partial core are preliminarily insulated and then hardened, the partial core is substantially non-conductive and the generation of eddy current can be suppressed. Here, when unevenness is formed on the end face of the partial core, the insulating coating of the metal particles is peeled off, and the adjacent metal particles become conductive. Therefore, when the technique described in Patent Document 4 is applied and a crossing groove is formed, a conductive surface having a two-dimensional expansion is formed on the surface of the partial core, and eddy current may be generated. There is. Therefore, in the reactor disclosed in the present specification, a dot-like depression or a linear groove that does not intersect with another groove is formed on the end surface of the partial core. In such depressions and grooves, although the insulating coating is peeled off and conducted, the conduction range is limited to a dotted or linear range, so that the generation of eddy currents can be suppressed. That is, even if an eddy current is generated, it is negligible, and a reduction in the reactor efficiency is suppressed. Therefore, the generation of eddy currents is suppressed by forming a plurality of dot-like depressions or linear grooves that do not intersect with other grooves on the end face of the partial core in which insulated metal particles are hardened. However, the bonding strength at the interface between the end face of the partial core and the resin can be significantly improved.

  Patent Document 5 discloses that the metal surface is roughened into a stripe shape, a dotted line shape, a wavy line shape, a knurled shape, or a satin shape in order to increase the bonding strength between the metal and the resin. It should be noted that Patent Document 5 lists only some aspects of unevenness on the metal surface, and does not mention the problem solved by the present invention of suppressing the generation of eddy currents.

  Also, the dot-like depressions and linear grooves are typically formed by irradiating the end face of the partial core with laser light. When the thermoplastic resin is poured into the end face of the partial core having such depressions and grooves, the resin enters the depressions and grooves and hardens. Thereby, compared with the case where the end surface of a partial core is a flat end surface without a dent and a groove | channel, the joint strength of the interface of a partial core and resin becomes large remarkably. Microscopically, the end face of the conventional partial core also has a certain degree of bonding strength because there is a fine gap between the particles of the raw material of the partial core, and the resin flows into the gap and hardens. However, for example, the size of the recesses and grooves formed by the laser beam is much larger than the size of the gaps between the raw material particles. (Including laser processing), the resin penetrates into the irregularities, and the bonding strength at the interface is dramatically improved. Even if the reactor vibrates during operation, the vibration noise of the reactor due to insufficient joint strength can be suppressed. In addition, the manufacturing cost can be reduced because a plate, an adhesive, and a heating furnace for bonding and fixing the facing partial cores are not necessary. Since these steps are not necessary, the manufacturing becomes easier.

  Details of the technology disclosed in this specification and further improvements will be described in detail in embodiments and examples of the invention.

The perspective view of a reactor is shown. The perspective view of a partial core is shown. The disassembled perspective view of the resin molding part by a core and primary insert molding is shown. Sectional drawing of the resin molding part by a core and primary insert molding is shown. Sectional drawing of the reactor before secondary insert molding is shown. The perspective view of the reactor before secondary insert molding is shown. The partial enlarged view of the end surface at the time of a hollow process being given to the end surface of a partial core is shown. The elements on larger scale of the end surface at the time of carrying out groove processing on the end surface of a partial core are shown. A cross-sectional view of the reactor is shown. The elements on larger scale of the interface of resin and the end surface of a partial core by secondary insert molding are shown. The disassembled perspective view of the core and resin molding part in the reactor of a modification is shown. Sectional drawing of the reactor of a modification is shown (before secondary insert molding). Sectional drawing of the reactor of a modification is shown.

  Some of the features of the examples are listed first. In addition, the following features are each useful by itself.

  (Feature 1) In the reactor of the embodiment, the gap between the opposed partial cores is filled with resin. By doing so, resin can join firmly with the end face of each partial core, and the partial cores which oppose can be joined reliably.

  The perspective view of the reactor 100 of an Example is shown in FIG. The reactor 100 is obtained by winding a coil 8 around a resin molded portion 4 (4a, 4b) that wraps a metal core (described later). Although mentioned later in detail, the resin molding part 4 is comprised by the substantially parallel two coil winding part, and the curved part which connects the edge parts of two coil winding parts, The whole is cyclic | annular. . The coil 8 is wound between the flanges 30 of the resin molding part 4. The coil 8 is covered with a resin coil cover 14 between the flanges 30. The coil cover 14 is provided with a window 15 for heat dissipation. The lead wire 12 of the coil 8 is drawn from between the flange 30 and the coil cover 14. A rectangular wire is used for winding the coil 8. A flat wire is a conducting wire having a rectangular cross section. Although the coil 8 is wound around two places of the resin molding part 4, since it is connected by one winding, it is one coil electrically. The step of molding the resin molding portion 4 that encloses the metal core is referred to as primary insert molding. On the other hand, after winding the coil 8 around the resin molding portion 4, the step of molding the coil cover 14 covering the coil 8 is referred to as secondary insert molding. The reactor 100 is used, for example, for an inverter or a voltage converter of an electric vehicle.

  As shown in FIG. 2, the core is composed of a pair of U-shaped cores 2 (2 a, 2 b) and two I-shaped cores 3. The pair of U-shaped cores 2 and the two I-shaped cores 3 correspond to an example of “partial cores”. The pair of U-shaped cores 2a and 2b are arranged so that the end faces face each other, and the I-shaped core 3 is interposed between the end face of one U-shaped core 2a and the end face of the other U-shaped core 2b. Are arranged, and the core is annular as a whole. The reactor 100 disclosed in the present embodiment has a plurality of dot-like depressions or linear grooves that do not intersect each other on the end faces of the U-shaped cores 2a and 2b, which are partial cores, and the I-shaped core 3. Is formed. This will be described in detail later.

  FIG. 3 is an exploded perspective view of the resin molded portions 4a and 4b and the core. Before assembling the entire core, each of the U-shaped cores 2a and 2b is covered with resin molded portions 4a and 4b. The step of forming the resin molding portion 4a (4b) so as to cover the U-shaped core 2a (2b) is the primary insert molding step. Specifically, the U-shaped core 2a (2b) is placed in a mold, and resin is injected around the end surface of the U-shaped core 2a (2b) to be molded. That is, the resin molded portion 4a (4b) is also formed in a U shape. Only the end face of the U-shaped core 2a (2b) is exposed, and the others are covered with resin. A guide portion 5 for positioning the I-shaped core 3 is formed at the end of the U-shaped resin molded portion 4a (4b). The guide part 5 is formed in a cylindrical shape so as to extend in parallel from both ends of the U-shaped core 2a (2b). After assembling the pair of U-shaped cores 2 a and 2 b across the I-shaped core 3, the coil is wound around the guide portion 5. A notch 21 is formed on the end surface of the guide portion 5.

  A protrusion 10 is formed inside the guide portion 5. The protrusions 10 are respectively formed at the four corners inside the rectangular cylindrical guide portion 5 (however, in FIG. 3, only one protrusion 10 appears and the other three protrusions are hidden. Please note.) The I-shaped core 3 is pushed in until it hits the protrusion 10. That is, the protrusion 10 determines the position of the I-shaped core 3 when the I-shaped core 3 is disposed inside the resin molding portion 4. The protrusion 10 forms a gap between the end surface of the U-shaped core 2a (2b) and the end surface of the I-shaped core 3, and the end surfaces do not directly contact each other. Also, two slits 32 are formed in the flange 30 of the resin molded portion 4b in FIG. As will be described later, the slit 32 is provided for passing the lead wire 12 of the coil 8.

  4 is a cross-sectional view of the core and the resin molded portion 4 in the XY plane of the coordinate system in the exploded view of FIG. FIG. 5 is a cross-sectional view of a reactor (hereinafter referred to as “reactor 90”) before secondary insert molding in the XY plane of FIG. 4 and 5 show a cross section crossing the notch 21. FIG. One half of the I-shaped core 3 is accommodated in the tube of the guide portion 5 of the one resin molded portion 4a. When the other half of the I-shaped core 3 is fitted so as to cover the guide portion 5 of the other resin molded portion 4b, the pair of U-shaped cores 2a and 2b and the I-shaped core 3 are arranged in an annular shape. (See FIG. 5).

  When the pair of resin molded portions 4a and 4b are combined with the I-shaped core 3 interposed therebetween, the end surfaces of the guide portions 5 of the pair of resin molded portions 4a and 4b come into contact with each other. A pair of resin molding parts 4a and 4b are joined by apply | coating an adhesive agent to the end surface of the guide part 5, and making a pair of resin molding parts 4a and 4b oppose. Thereby, the notch 21 formed in the end surface of the guide part 5 becomes a through hole which communicates the inside and outside of the resin molded part 4. The coil 8 is formed in a coil shape in advance, and is passed through the end portions of the U-shaped resin molded portions 4a and 4b prior to combining the pair of resin molded portions 4a and 4b. FIG. 5 shows the semi-finished reactor 90 at this point. As described above, the I-shaped core 3 is positioned by the protrusion 10. Thereby, the end surface of the U-shaped core 2 does not contact the end surface of the I-shaped core 3, and a gap 41 is formed therebetween. As will be described later, in the secondary insert molding for molding the resin coil cover 14, the resin is filled into the gap 41 through the above-described through hole. By filling the gap 41 with the resin, the U-shaped core 2 and the I-shaped core 3 are joined via the resin. That is, the notch 21 is provided to fill the internal gap 41 with resin after joining the pair of resin molded portions 4. At this point, the I-shaped core 3 is only positioned by the protrusion 10 inside the guide portion 5 and is not fixed.

  6 shows a perspective view of the reactor 90 of FIG. As described above, the lead wire 12 of the coil 8 extends through the slit 32 provided in the flange 30 of the resin molding portion 4b. When the coil cover 14 is formed around the coil 8 of the reactor 90 (semi-finished product) shown in FIG. 6, the reactor 100 shown in FIG. 1 is completed. Secondary insert molding for molding the coil cover 14 will be described later.

  Next, the end surfaces of the U-shaped core 2 and the I-shaped core 3 in the reactor 100 of the present embodiment (that is, the surface facing the gap 41) will be described. Hereinafter, for convenience of explanation, these end faces are collectively referred to as “core end faces”. FIG. 7 shows a partially enlarged view of the end face of the U-shaped core 2 (region indicated by reference numeral VII in FIG. 2). FIG. 7 shows a state in which a plurality of dot-like depressions 6 are formed on the end face of the U-shaped core 2a. The depressions 6 are formed so as to be uniformly distributed over the entire core end face. The recess 6 is formed by laser light irradiation. The depressions 6 are circular with a radius r1 and are formed at equal intervals. The distance between the centers of the recesses 6 is L1, and 2r1 <L1. L1 is preferably a distance such that the sputtered particles generated by laser processing adhere to the end surface of the core, so that adjacent recesses 6 do not conduct. r1 is, for example, 0.15 mm and L1 is, for example, 0.5 mm, but is not limited to this value. The depth of the recess 6 is, for example, 0.1 mm, but is not limited to this value. A recess similar to the recess 6 shown in FIG. 7 is also formed on the other core end face.

  What is formed in the core end face is not limited to the dot-like depression 6 but may be a linear groove. FIG. 8 shows an example of a linear groove that can be formed instead of the dot-like depression 6. FIG. 8 corresponds to a partially enlarged view of VII in FIG. FIG. 8 shows a state in which a linear groove 16 is formed on the end face of the U-shaped core 2a by overlapping a plurality of point-like depressions. The groove 16 is uniform over the entire core end face. Is formed. The groove 16 is formed by laser light irradiation. The dot-like depressions constituting the groove 16 are circular with a radius r2, and are formed so that the depressions overlap each other. The distance between the centers of the adjacent recesses that overlap is L2, and the relationship 0 <L2 <2r2 holds. The grooves 16 are formed so as not to cross each other. That is, the grooves 16 are parallel to each other. The distance between adjacent grooves 16 is L3, and 2r2 <L3. L3 is preferably such a distance that the adjacent grooves 16 do not conduct each other when sputtered particles generated by laser processing adhere to the end face of the core. r2 is, for example, 0.15 mm, L2 is, for example, 0.2 mm, and L3 is, for example, 0.5 mm, but is not limited to this value. The depth of the groove 16 is, for example, 0.1 mm, but is not limited to this value.

  Returning to FIG. 5, the secondary insert molding will be described. In the secondary insert molding, another mold is attached so as to cover the coil 8 of the semi-finished reactor 90 (see FIG. 6), and resin is injected into the mold. The injected resin is solidified around the coil 8 to form the coil cover 14. When the resin is injected into the mold, the resin is filled into the gap 41 inside the resin molding portion 4 through the through hole formed by the notch 21. Although not shown in FIG. 5, in order to remove the resin flow path and the air and gas in the gap 41 so that the resin is reliably filled in the gap 41 inside the resin molding portion 4. The opening is secured. When the resin is filled in the gap 41, the resin enters the plurality of dot-like depressions 6 or the plurality of grooves 16 formed on the core end surface. FIG. 9 shows a cross-sectional view of the reactor 100 after the secondary insert molding, across the notch 21. As shown in FIG. 9, the gap 41 is filled with a resin 42. The resin 42 is also filled in the gap between the two rows of coils. FIG. 10 is a partially enlarged view of a region indicated by X in FIG. FIG. 10 is an enlarged view of a cross section of the interface between the end face of the U-shaped core 2 b and the resin 42. Since the U-shaped core 2b is made by solidifying (typically sintering) metal particles having an insulating coating on the surface, microscopically, it is an aggregate of particles as shown in FIG. . A plurality of point-like depressions 6 or a plurality of grooves 16 are formed on the end face of the U-shaped core 2b. As described above, when the resin 42 is poured through the through hole in the secondary insert molding process, the resin 42 is filled in the gap 41 and enters the recess 6 or the groove 16 to be hardened.

  The advantage regarding the reactor 100 of an Example is described. The end faces of the U-shaped core 2 and the I-shaped core 3 of the reactor 100 intersect with a plurality of point-like depressions 6 or other grooves as shown in FIGS. The linear groove | channel 16 which does not do is formed. Thus, when the resin 42 is filled in the secondary insert molding process, the resin 42 enters and hardens into the recesses 6 and the grooves 16 as shown in FIG. The joint strength at the interface with the core end face is remarkably improved. Microscopically, there is a fine gap between the metal particles on the end face of the core, and when the resin 42 enters, a certain degree of anchor effect is generated. However, as shown in FIG. 10, the recess 6 or the groove 16 artificially cut by laser light irradiation or the like is much larger than the gap between the metal particles, so that the anchor effect is increased accordingly. That is, the U-shaped core 2 and the I-shaped core 3 are firmly joined by the resin 42.

  Here, if the U-shaped core and the I-shaped core are conductive, the magnetic flux generated in the coils passes through these cores, and an eddy current is generated inside the core. Since the eddy current generates a counter electromotive force in the coil, the efficiency of the reactor is lowered. For this reason, the metal particles that are the raw materials of these cores are hardened after being subjected to an insulation treatment with an insulation coating or the like in advance. By doing so, the core as a whole becomes non-conductive, and generation of eddy current can be suppressed. However, when the end surface of the core is artificially cut with a laser beam or the like, the insulating coating of the metal particles at the cut portion is peeled off, and the metal particles at the cut portion are conducted. When a pattern having a two-dimensional spread, such as a crossing groove, is formed at the time of cutting, an eddy current may be generated because the conduction region expands in a planar shape. Thus, as in the present embodiment, by performing a cutting process in the form of a dot or a line that does not intersect with other grooves, conduction in a planar shape is prevented, and generation of eddy currents is suppressed. Since the conduction surface is limited to a dotted or linear range, an eddy current is generated, but it is suppressed to a slight extent. In addition to preventing the reactor efficiency from being reduced due to the generation of eddy currents, the joint strength between the resin and the metal core end surface can be dramatically improved by artificially cutting the core end surface. The same applies to the case where the recess or groove is formed by cutting with a physical blade instead of a laser.

  Moreover, the core can be reliably insulated from the coil by covering the U-shaped core 2 with the resin molded portion 4 by primary insert molding and then placing the I-shaped core 3 on the guide portion 5 of the resin molded portion 4. Furthermore, by covering the periphery of the coil 8 and the resin molding portion 4 with a resin coil cover 14, the coil 8 is securely fixed to the resin molding portion 4 (that is, the core). By firmly joining the U-shaped core 2 and the I-shaped core 3, even if the reactor vibrates during operation, the vibration noise of the reactor due to insufficient joint strength can be suppressed. In addition, since an adhesive for bonding the opposing cores and a heating furnace for bonding and fixing are not required, the manufacturing cost can be reduced. Since these steps are not necessary, the manufacturing becomes easier.

  Points to be noted regarding the reactor 100 of the embodiment will be described. In FIG. 8, the linear groove 16 is formed in the Z-axis direction, but the direction of the groove is not limited to this. The grooves may be formed in any direction as long as the grooves are parallel to each other. Moreover, as long as the groove | channels do not cross | intersect, it does not need to be parallel. For example, the plurality of grooves may be formed so as to extend radially from the center of the core end surface. Furthermore, the position and the number of the notches 21 provided at the end of the guide part 5 are limited to the positions and the numbers described in the above embodiments as long as the secondary insert molding can be appropriately performed. I can't.

  Moreover, the unevenness | corrugation formed in each end surface of a U-shaped core or an I-shaped core does not need to be the same pattern. For example, a plurality of point-like depressions may be formed on the end surface of the U-shaped core, and grooves that do not intersect with each other may be formed on the end surface of the I-shaped core. Furthermore, if the conductive surface is not flat, a recess and a groove may be formed on the core end surface.

  In addition to insert molding by setting the core in a mold, the resin molding portion 4 may be one in which the core is fitted after separately injection molding. Moreover, the reactor 100 of an Example was the structure by which all the gaps between the U-shaped core and I-shaped core which oppose are filled with resin. There may not be an I-shaped core, or a plurality of I-shaped cores may be arranged continuously. Further, a plate may be disposed between the U-shaped cores or between the U-shaped core and the I-shaped core. Next, a reactor having a plate will be described.

  The reactor of a modification is demonstrated. The reactor of a modification differs from the reactor 100 of an Example by the point which has the plate made from the nonmagnetic material between the U-shaped core and the I-shaped core. FIG. 11 shows an exploded perspective view of the resin molding portions 104a and 104b of the reactor and the core of the modified example. It should be noted that in the drawings after FIG. 11, reference numerals are omitted for the same parts (portions) as the reactor 100 of the embodiment.

  In this modification, the plate 7 is disposed between the U-shaped core 2 a and the I-shaped core 3 and between the U-shaped core 2 b and the I-shaped core 3. As will be described later, the plate 7 is disposed so as to have a gap (space) between the end surface of the U-shaped core 2 and the end surface of the I-shaped core 3. The plate 7 is made of a nonmagnetic material. The material of the plate 7 is, for example, alumina ceramics.

  As shown in FIG. 11, before assembling the entire core, the U-shaped cores 2a and 2b are covered with resin molded portions 104a and 104b, respectively. The step of forming the resin molding portion 104a (104b) so as to cover the U-shaped core 2a (2b) is the primary insert molding step described in the embodiment. After the primary insert molding, only the end face of the U-shaped core 2a (2b) is exposed and the others are covered with resin. A guide portion 105 for positioning the I-shaped core 3 and the plate 7 is formed at the end of the U-shaped resin molded portion 104a (104b). The guide part 105 is formed in a cylindrical shape so as to extend in parallel from both ends of the U-shaped core 2a (2b). After assembling the pair of U-shaped cores 2 a and 2 b with the I-shaped core 3 and the plate 7 interposed therebetween, a coil is wound around the guide portion 105. A cutout 21 is formed on the end surface of the guide portion 105.

  Inside the guide portion 105, a protrusion 9a and a protrusion 9b are formed. The protrusions 9a are respectively formed on the inner sides of the two side surfaces of the guide portion 105 that intersect perpendicularly with the Z-axis direction in FIG. The protrusions 9b are respectively formed on the inner sides of the two side surfaces of the guide portion 105 that intersect perpendicularly with the Y-axis direction. The plate 7 is pushed in until it hits the protrusion 9 a of the guide portion 105. That is, the protrusion 9 a determines the position of the plate 7 when the plate 7 is disposed inside the resin molding portion 104. The plate 7 is made such that the length in the Y-axis direction is shorter than the inner length in the Y-axis direction of the guide portion 5 so that the projection 7b cannot be held when the plate 7 is pushed. On the other hand, the function of the protrusion 9 b is the same as the function of the protrusion 10 in FIG. 3, and the position of the I-shaped core 3 is determined when the I-shaped core 3 is disposed inside the resin molding portion 104. The protrusion 9a forms a gap between the plate 7 and the end faces of the U-shaped cores 2a and 2b, so that the end faces do not directly contact each other. Similarly, the protrusion 9b forms a gap between the plate 7 and the end surface of the I-shaped core 3, and the end surfaces do not directly contact each other.

  FIG. 12 is a cross-sectional view of an assembly in which resin molding portions 104a and 104b of a reactor according to a modified example are combined. FIG. 12 shows a cross section crossing the notch 21 as in FIG. 5. Half of the I-shaped core 3 is accommodated in the cylinder of the guide portion 105 of one resin molding portion 104 a via the plate 7. When the other half of the I-shaped core 3 is fitted through the other plate 7 so as to cover the guide portion 105 of the other resin molded portion 104b, a pair of U-shaped cores 2a and 2b and an I-shaped core 3 becomes an annular arrangement.

  When the pair of resin molding portions 104a and 104b are opposed to each other with the plate 7 and the I-shaped core 3 interposed therebetween, the notch 21 formed on the end surface of the guide portion 105 communicates the inside and outside of the resin molding portion 104. It becomes a through hole. The coil 8 is formed in a coil shape in advance, and is passed through the end portions of the U-shaped resin molded portions 104a and 104b prior to combining the pair of resin molded portions 104a and 104b. FIG. 12 shows the semi-finished reactor 90a at this point. As in the case of the reactor 100 of the embodiment, the end surface of the U-shaped core 2 does not contact the end surface of the I-shaped core 3, and a gap 141 is formed therebetween. In secondary insert molding for molding the resin coil cover 14, the resin is filled in the gap 141 through the above-described through hole. By filling the gap 141 with resin, the U-shaped core 2 and the I-shaped core 3 are joined with the plate 7 interposed therebetween. That is, the notch 21 is provided to fill the internal gap 141 with resin after the pair of resin molded portions 104 are joined. At this time, the plate 7 and the I-shaped core 3 are only positioned by the protrusion 9a and the protrusion 9b in the guide portion 105, but are not fixed.

  Secondary insert molding in which the coil 8 is covered with resin and the resin is poured into the gap 141 is performed on the semi-finished reactor 90a (see FIG. 12). In the secondary insert molding, the resin is filled into the gap 141 inside the resin molding portion 104 through the through hole formed by the notch 21. Although not shown in FIG. 12, the resin flow path and the air in the gap 141 are filled in the resin molding portion 104 so that the resin is reliably filled in the gap 141 around the plate 7. And an opening for venting gas. In FIG. 13, sectional drawing which crosses the notch 21 of the reactor 100a after secondary insert molding is shown. As shown in FIG. 13, the gap 141 around the plate 7 is filled with the resin 42. The resin 42 is also filled in the gap between the two rows of coils.

  Also in the reactor 100a of the modified example, as in the first embodiment, a plurality of dot-like depressions or a plurality of grooves (grooves that do not intersect with other grooves) are formed on the end surface of the core. The resin enters the groove, and the resin and the core are firmly bonded.

  Points to be noted regarding the reactor 100a according to the modification will be described. In the reactor 100a, a non-magnetic plate 7 is disposed between the U-shaped core 2 and the I-shaped core 3. By filling the resin 42 around the plate 7 so as to cover the plate 7, The U-shaped core 2 and the I-shaped core 3 are firmly bonded via the resin 42. The opposing cores can be reliably joined. At the same time, when the nonmagnetic plate is made of ceramic or the like, the heat resistance at the interface between the resin and the plate can be improved. The protrusion 9a may be formed on the side surface perpendicular to the Y-axis direction instead of being formed on the side surface of the guide portion 105 that intersects the Z-axis direction perpendicularly. Similarly, the protrusion 9b may be formed on the side surface perpendicular to the Z-axis direction instead of being formed on the side surface of the guide portion 105 perpendicular to the Y-axis. In this case, the plate 7 may have a shape that cannot be held by the protrusion 9b when the plate 7 is disposed on the guide portion 105 of the resin molding portion 104. Furthermore, the position and number of the protrusions 9a and 9b are not limited to the above as long as a gap is formed on both sides of the plate 7 in the X-axis direction. In addition, the reactor 100a of a modification is provided with the same advantage as the reactor 100 of the Example demonstrated previously.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

2a, 2b: U-shaped core 3: I-shaped core 4a, 4b, 104a, 104b: Resin molding part 5: Guide part 6: Depression 7: Plate 8: Coil 9a, 9b, 10: Protrusion 12: Lead wire 14 : Coil cover 15: window 16: groove 21: notch 30: flange 32: slit 41, 141: gap 42: resin 90, 90a: reactor 100, 100a: reactor before secondary insert molding processing

Claims (3)

A core in which at least two partial cores face each other across a gap, and an end surface of the partial core facing the gap is covered with a resin;
A coil wound around a core;
A reactor comprising
A reactor characterized in that a plurality of dot-like depressions or linear grooves that do not intersect with other grooves are formed on the end face.   The reactor according to claim 1, wherein the partial core is formed by solidifying metal particles subjected to insulation treatment.   The reactor according to claim 1, wherein the gap is filled with a resin.

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